Dart: Blur effect

BlurDemo.dart

import 'dart:ui';
import 'package:flutter/material.dart';

class FrostedDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: Center (
      child: Stack(
        children: <Widget>[
          Positioned.fromRect(
              child: FlutterLogo(),
            rect: Rect.fromLTRB(50, 50, 250, 250),
          ),
          Positioned.fill(
              child: BackdropFilter(
                filter: ImageFilter.blur(sigmaX: 5, sigmaY: 5),
                child: Container(
                  color: Colors.white.withOpacity(0),
                ),
              ),

          )
        ]
      )
      )
    );
  }

}